Methods and apparatus for making a determination about an eye in ambient lighting conditions

ABSTRACT

Disclosed herein are methods and apparatus for making a determination about an eye in ambient lighting conditions comprising detecting ambient light reflected out of an eye of a subject from a retina of the eye of the subject and making a determination about the eye of the subject based upon the reflected ambient light.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 14/934,742 filed Nov. 6, 2015, which claimspriority to and benefit of U.S. provisional patent application Ser. No.62/076,804 filed Nov. 7, 2014, both of which are fully incorporated byreference and made parts hereof.

BACKGROUND

There are many existing devices that are used to detect the opticalquality of the eye or other optical systems, including:autorefractors/ophthalmic refractometers, aberrometers, etc. All of theexisting devices work by using a light source to illuminate the eye.Many devices, including the vast majority of autorefractors, use aninfrared light source, but visible light sources are also used. Anyonewho has used a standard camera with a flash will know that light fromthe flash will reflect off of the retina during photography. Thisreflected light will make the pupil appear red in a photograph of ahuman eye or appear greenish in a photograph of many animals' eyes. Thereflected light will also have a particular pattern that is dependentupon the eye's optical distortions. Many existing/previousautorefractors or aberrometers are based on this principle, i.e.,shining a light into the eye and then detecting the pattern of thereflected light after it has been distorted by the eye. The devices varyin the configuration or type of light source or in how the reflectedlight is detected (single images, lenslet arrays, telescope combinedwith a lenslet array, etc.). However, in each of those cases, a light isshined into the eye and then the magnitude of the refractive error isdetermined, and this is often based on the intensity slope of the light(brighter at either the top or the bottom of the pupil) that isreflected off of the retina and back out of the eye.

Therefore, methods, apparatus and systems are desired that improve thedetection of an optical quality of the eye or other optical system andthat overcome challenges in the art, some of which are described above.

SUMMARY

Described herein are devices and methods to measure optical distortionsin the eye by monitoring the intensity of a first color of light versusintensity of a second color of light within the pupil of a subject underambient lighting conditions, which is readily available light where noemitter of light is shined into the eye. For example, although there maybe lamps and light fixtures in a room wherein devices and methodsdescribed in this disclosure are practiced, these sources or emitters oflight are not used purposefully to illuminate the eye and the source oflight is not directed into the eye. The subject can be a human or ananimal. While the pupil may appear to be black or very dark in aphotograph that does not use a flash, the pixel values do vary inmagnitude based on the power of the eye. In the images that are obtainedfor embodiments of this invention, the information needed to measure theoptical distortions of the eye is contained within the pixel values ofthe first and second color.

Non-relevant reflections from the lens and corneal surface are blocked;else these reflections would otherwise obscure measurement of the lightwithin the pupil. For example, the surface closest to the patient of theapparatus acquiring the images can be matte and black so that it doesnot create corneal reflections that would obscure the measurement, or apolarizing filter can be used.

Once this image is obtained, the pupil and its border are identified.Light within the pupil is then analyzed. No light is shined into theeye. The total intensity of the pupil is used in a formula thatcalculates the autorefraction result, and a minimum intensity isrequired, but differences in intensity across the pupil are not measuredfor autorefraction. The light in an eye with spherical refractive errordoes not have a slope; it is of uniform intensity within the pupil. Eventhe difference between the pixels of the first color and the secondcolor is uniform across the pupil for spherical refractive error (i.e.,no astigmatism). Ambient light from the room that is always reflectingoff of the retina is measured. A difference in the intensity of thefirst color versus the second color pixel values is determined andcompared; this difference is related to the eye's refractiveerror/glasses prescription. For example, the difference between thefirst color and second color pixels is a larger number in hyperopia(farsighted) and a lower number in myopia (nearsighted). Also, the lightwithin the pupil of eyes with hyperopia is somewhat brighter than eyeswith myopia. In the case of astigmatism, the intensity of individualpixels across the pupil will have a higher standard deviation than withhyperopia or myopia alone. In most eyes, the axis of the astigmatism isknown to be regular, meaning that the two principal power meridians are90 degrees apart. In the present disclosure, the presence of astigmatismwithin an optical system causes differences in intensity within thepupil. The more myopic meridian will be dimmer and the more hyperopicmeridian will be brighter.

Disclosed herein is a method of making a determination about an eye. Themethod comprises detecting, using a computing device, ambient lightreflected out of an eye of a subject from a retina of the eye of thesubject; and making a determination about the eye of the subject basedupon the reflected ambient light. As described herein, the reflectedlight relies upon ambient light and no additional light emitter isrequired or directed toward the eye to create the reflected light. Thedetermination about the eye is made based at least in part on an aspectof the reflected ambient light. For example, overall brightness and theintensity of one or more colors of the reflected ambient light can beused to make the determination about the eye.

In one aspect, the determination made about the eye comprises therefractive error for the eye of the subject based at least in part on anaspect of the reflected ambient light.

Alternatively, or optionally, in reference to the above-describedmethod, detecting, using the computing device, ambient light reflectedout of an eye of a subject from a retina of the eye of the subject canfurther comprise capturing, using an image capture device, an image ofthe eye of a subject, wherein the image is captured using only ambientlighting conditions and wherein non-relevant reflections from the eye ofthe subject are managed while capturing the image; determining, usingthe computing device, an overall intensity of light from a plurality ofpixels located within the at least a portion of a pupil captured in theimage; determining, using the computing device, a first intensity of afirst color from the plurality of pixels located within the at least aportion of a pupil of the eye of the subject captured in the image;determining, using the computing device, a second intensity of a secondcolor from the plurality of pixels located within the at least a portionof the pupil of the eye of the subject captured in the image; andcomparing, by the computing device, a relative intensity of the firstcolor and a relative intensity of the second color, wherein thecomparison and the overall intensity are used to make the determinationabout the eye of the subject based upon the reflected ambient light.Either the first or the second color can be any one or any combinationof red green and blue.

In one aspect, the above described method can be used to makedeterminations about the eye that include an autorefraction or aphotorefraction measurement. For example, capturing, using the imagecapture device, an image of the eye of the subject can comprisecapturing a first image using only ambient lighting conditions with theimage capture device through a spectacle lens or a contact lens whilethe subject is wearing the spectacle lens or the contact lens over theeye and capturing a second image using only ambient lighting conditionswith the image capture device while the subject is not wearing thespectacle lens or the contact lens over the eye and the first image iscompared to the second image and the determination about the eye of thesubject based upon the reflected ambient is based on the comparison andcomprises an estimated prescription for the spectacle lens or thecontact lens.

Alternatively, or optionally, in reference to the above-describedmethod, when the first intensity of the first color is brighter relativeto the second intensity of the second color and the overall intensity isrelatively brighter, the determination about the eye of the subjectbased upon the reflected ambient light comprises a positive value orhyperopia. Similarly, when the first intensity of the first color isdimmer relative to the second intensity of the second color and theoverall intensity is relatively dimmer, the determination about the eyeof the subject based upon the reflected ambient light comprises anegative value or myopia.

The above-described method can also be used to make a determinationabout the eye such as astigmatism. For example, the method can furthercomprise making a first determination about the eye of the subject basedupon the reflected ambient light from a first plurality of pixelslocated within the at least a portion of the pupil of the eye of thesubject captured in the image; making a second determination from asecond plurality of pixels located within the at least a portion of thepupil of the eye of the subject captured in the image, wherein thesecond plurality of pixels are a subset of the first plurality ofpixels; making a third determination from a third plurality of pixelslocated within the at least a portion of the pupil of the eye of thesubject captured in the image, wherein the third plurality of pixels area subset of the first plurality of pixels and are separate from thesecond plurality of pixels; and comparing the first determination, thesecond determination and the third determination to make thedetermination about the eye of the subject based upon the reflectedambient light. Comparing the first determination, the seconddetermination and the third determination to make the determinationabout the eye of the subject based upon the reflected ambient light cancomprise one or more of determining a standard deviation of the firstdetermination to the second determination, a standard deviation of thefirst determination to the second determination, or a standard deviationof the second determination to the third determination, wherein thedetermined standard deviation indicates the determination about the eyeof the subject based upon the reflected ambient light. As noted above,the determination about the eye of the subject based upon the reflectedambient light can be a presence or an absence of astigmatism. Further,when the presence of astigmatism is detected, an amount of astigmatismcan be determined by comparing the overall intensity and the relativeintensity of the first color or the relative intensity of the secondcolor of various regions of the pupil.

As noted above, the method comprises managing non-relevant reflectionsfrom the eye while capturing the image. Generally, this comprisesmanaging reflections from a cornea or a lens of the eye of the subjectwhile capturing the image. For example, managing non-relevantreflections from the eye while capturing the image can comprise placinga polarizing filter over a lens of the image capture device or betweenthe image capture device and the eye of the subject. Alternative oroptionally, managing non-relevant reflections from the eye whilecapturing the image can comprise blocking light that would lead toreflections from a corneal surface of the eye or a lens of the eye. Forexample, managing non-relevant reflections from the eye while capturingthe image can comprise providing a surface that absorbs light orprevents the non-relevant reflections from the eye while capturing theimage. The surface can have a black matte finish. In one aspect, thesurface can comprise a portion of the image capture device. For example,the surface can comprise at least a portion of a case that houses theimage capture device.

In reference to the above-described method, the image capture device cancomprise a smart phone or other mobile computing device having a camera.Generally, the image capture device can capture a still image or a videoof the eye of the subject.

The above-described method can be used to make a determination about theeye of a person having a smaller than average pupil. For example, wherethe subject's pupil has a diameter of approximately 2 mm or less.Further, the subject's pupil can be a natural pupil or an artificialpupil. The eye of the subject can be the subject's left eye or righteye, or the subject's left eye and right eye. In one aspect, the methodcan further comprise detecting an intensity for the ambient lightconditions and providing an indication if the ambient light conditionsare too low for the image capture device to capture the image of the eyeof the subject.

Also disclosed herein is an alternate method of making a determinationabout an eye. The method comprises capturing, using an image capturedevice, an image of an eye of a subject, wherein the image is capturedusing only ambient lighting conditions and wherein non-relevantreflections from a cornea and a lens of the eye of the subject aremanaged while capturing the image; determining, using a computingdevice, an overall intensity of light from a plurality of pixels locatedwithin at least a portion of a pupil captured in the image, wherein theplurality of pixels comprise red, green and blue pixels; determining,using the computing device, an average red intensity from the pluralityof pixels located within the at least a portion of the pupil captured inthe image; determining, using the computing device, an average blueintensity from the plurality of pixels located within the at least aportion of a pupil captured in the image; and determining, by thecomputing device, using the average red intensity, the average blueintensity and the determined overall intensity an optical quality of theeye.

Similarly as described above, the determined optical quality of the eyecan comprise an autorefraction or photorefraction measurement such thatthe method can be used to provide an estimated prescription forspectacle lens or contact lens. Further, the method can be used todetermine an optical quality of the eye such as a positive value orhyperopia, a negative value or myopia, the presence or absence ofastigmatism, and an amount of astigmatism if is found to be present.

Another aspect of the disclosure is an apparatus for performing theabove-described methods. In one embodiment, the apparatus comprises animage capture device; a memory; and a processor in communication withthe memory and the image capture device, wherein the processor executescomputer-readable instructions stored in the memory that cause theprocessor to: capture, using the image capture device, an image of aneye of a subject, wherein the image is captured using only ambientlighting conditions and wherein non-relevant reflections from the eye ofthe subject are managed while capturing the image; detect, from theimage of the eye of the subject, ambient light reflected out of the eyeof a subject from a retina of the eye of the subject; and make adetermination about the eye of the subject based upon the detectedreflected ambient light.

In one aspect, the determination made about the eye by the apparatuscomprises the refractive error for the eye of the subject based at leastin part on an aspect of the reflected ambient light.

Alternatively, or optionally, the apparatus can be used for detectingambient light reflected out of an eye of a subject from a retina of theeye of the subject by determining an overall intensity of light from aplurality of pixels located within the at least a portion of a pupilcaptured in the image; determining a first intensity of a first colorfrom the plurality of pixels located within the at least a portion of apupil of the eye of the subject captured in the image; determining asecond intensity of a second color from the plurality of pixels locatedwithin the at least a portion of the pupil of the eye of the subjectcaptured in the image; and comparing a relative intensity of the firstcolor and a relative intensity of the second color, wherein thecomparison and the overall intensity are used to make the determinationabout the eye of the subject based upon the reflected ambient light.Either the first or the second color can be any one or any combinationof red green and blue.

In one aspect, the above described apparatus can make determinationsabout the eye that include an autorefraction or a photorefractionmeasurement. For example, when capturing, using the image capturedevice, an image of the eye of the subject the processor can executecomputer-readable instructions store in the memory to capture a firstimage using only ambient lighting conditions with the image capturedevice through a spectacle lens or a contact lens while the subject iswearing the spectacle lens or the contact lens over the eye and capturea second image using only ambient lighting conditions with the imagecapture device while the subject is not wearing the spectacle lens orthe contact lens over the eye and the first image is compared to thesecond image and the determination about the eye of the subject basedupon the reflected ambient is based on the comparison and comprises anestimated prescription for the spectacle lens or the contact lens.

Alternatively, or optionally, the processor of the apparatus can executecomputer-readable instructions such that when the first intensity of thefirst color is brighter relative to the second intensity of the secondcolor and the overall intensity is relatively brighter, thedetermination about the eye of the subject based upon the reflectedambient light comprises a positive value or hyperopia. Similarly, whenthe first intensity of the first color is dimmer relative to the secondintensity of the second color and the overall intensity is relativelydimmer, the determination about the eye of the subject based upon thereflected ambient light comprises a negative value or myopia.

The above-described apparatus can also be used to make a determinationabout the eye such as astigmatism. For example, the processor of theapparatus can execute computer-readable instructions for making a firstdetermination about the eye of the subject based upon the reflectedambient light from a first plurality of pixels located within the atleast a portion of the pupil of the eye of the subject captured in theimage; making a second determination from a second plurality of pixelslocated within the at least a portion of the pupil of the eye of thesubject captured in the image, wherein the second plurality of pixelsare a subset of the first plurality of pixels; making a thirddetermination from a third plurality of pixels located within the atleast a portion of the pupil of the eye of the subject captured in theimage, wherein the third plurality of pixels are a subset of the firstplurality of pixels and are separate from the second plurality ofpixels; and comparing the first determination, the second determinationand the third determination to make the determination about the eye ofthe subject based upon the reflected ambient light. Comparing the firstdetermination, the second determination and the third determination tomake the determination about the eye of the subject based upon thereflected ambient light can comprise one or more of determining astandard deviation of the first determination to the seconddetermination, a standard deviation of the first determination to thesecond determination, or a standard deviation of the seconddetermination to the third determination, wherein the determinedstandard deviation indicates the determination about the eye of thesubject based upon the reflected ambient light. As noted above, thedetermination about the eye of the subject based upon the reflectedambient light can be a presence or an absence of astigmatism. Further,when the presence of astigmatism is detected, an amount of astigmatismcan be determined by comparing the overall intensity and the relativeintensity of the first color or the relative intensity of the secondcolor of various regions of the pupil.

As noted above, the apparatus can manage non-relevant reflections fromthe eye while capturing the image. Generally, this comprises managingreflections from a cornea or a lens of the eye of the subject whilecapturing the image. For example, managing non-relevant reflections fromthe eye while capturing the image can comprise placing a polarizingfilter over a lens of the image capture device or between the imagecapture device and the eye of the subject. Alternative or optionally,managing non-relevant reflections from the eye while capturing the imagecan comprise blocking light that would lead to reflections from acorneal surface of the eye or a lens of the eye. For example, managingnon-relevant reflections from the eye while capturing the image cancomprise providing a surface that absorbs light or prevents thenon-relevant reflections from the eye while capturing the image. Thesurface can have a black matte finish. In one aspect, the surface cancomprise a portion of the image capture device. For example, the surfacecan comprise at least a portion of a case that houses the image capturedevice.

In reference to the above apparatus, the image capture device cancomprise a smart phone or other mobile computing device having a camera.Generally, the image capture device can capture a still image or a videoof the eye of the subject.

The above-described apparatus can be used to make a determination aboutthe eye of a person having a smaller than average pupil. For example,where the subject's pupil has a diameter of approximately 2 mm or less.Further, the subject's pupil can be a natural pupil or an artificialpupil. The eye of the subject can be the subject's left eye or righteye, or the subject's left eye and right eye. In one aspect, theapparatus can further comprise a light meter to detect an intensity forthe ambient light conditions and provide an indication if the ambientlight conditions are too low for the image capture device to capture theimage of the eye of the subject.

It should be understood that the above-described subject matter may alsobe implemented as a computer-controlled apparatus, a computer process, acomputing system, or an article of manufacture, such as acomputer-readable storage medium.

Other systems, methods, features and/or advantages will be or may becomeapparent to one with skill in the art upon examination of the followingdrawings and detailed description. It is intended that all suchadditional systems, methods, features and/or advantages be includedwithin this description and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The components in the drawings are not necessarily to scale relative toeach other. Like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 illustrates an exemplary overview apparatus for making adetermination about the eye of a subject in ambient lighting conditions;

FIG. 2A illustrates an example of an apparatus for capturing an image ofthe eye and making a determination about an eye in ambient lightingconditions;

FIG. 2B illustrates an image of the eye captured by an apparatus forcapturing an image of the eye and making a determination about an eye inambient lighting conditions;

FIG. 2C illustrates an example of an apparatus for capturing an image ofthe eye and making a determination about an eye in ambient lightingconditions;

FIG. 2D illustrates an image of an eye that can be used to make adetermination about the eye such as astigmatism;

FIG. 2E illustrates an example of an apparatus for capturing an image ofthe eye using polarizing filters and making a determination about an eyein ambient lighting conditions;

FIG. 2F illustrates an example of an apparatus for capturing an image ofthe eye using a surface and making a determination about an eye inambient lighting conditions;

FIG. 3 illustrates an example computing device upon which embodiments ofthe invention may be implemented;

FIG. 4 illustrates an example method for making a determination about aneye of a subject based upon ambient light reflected out of the eye; and

FIG. 5 illustrates an alternate example method for making adetermination about an eye of a subject based upon ambient lightreflected out of the eye.

DETAILED DESCRIPTION

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art. Methods and materials similar or equivalent to those describedherein can be used in the practice or testing of the present disclosure.

As used in the specification and the appended claims, the singular forms“a,” “an” and “the” include plural referents unless the context clearlydictates otherwise. Ranges may be expressed herein as from “about” oneparticular value, and/or to “about” another particular value. When sucha range is expressed, another embodiment includes from the oneparticular value and/or to the other particular value. Similarly, whenvalues are expressed as approximations, by use of the antecedent“about,” it will be understood that the particular value forms anotherembodiment. It will be further understood that the endpoints of each ofthe ranges are significant both in relation to the other endpoint, andindependently of the other endpoint.

“Optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, and that the description includesinstances where said event or circumstance occurs and instances where itdoes not.

Throughout the description and claims of this specification, the word“comprise” and variations of the word, such as “comprising” and“comprises,” means “including but not limited to,” and is not intendedto exclude, for example, other additives, components, integers or steps.“Exemplary” means “an example of” and is not intended to convey anindication of a preferred or ideal embodiment. “Such as” is not used ina restrictive sense, but for explanatory purposes.

Disclosed are components that can be used to perform the disclosedmethods and systems. These and other components are disclosed herein,and it is understood that when combinations, subsets, interactions,groups, etc. of these components are disclosed that while specificreference of each various individual and collective combinations andpermutation of these may not be explicitly disclosed, each isspecifically contemplated and described herein, for all methods andsystems. This applies to all aspects of this application including, butnot limited to, steps in disclosed methods. Thus, if there are a varietyof additional steps that can be performed it is understood that each ofthese additional steps can be performed with any specific embodiment orcombination of embodiments of the disclosed methods.

The present methods and systems may be understood more readily byreference to the following detailed description of preferred embodimentsand the Examples included therein and to the Figures and their previousand following description.

FIG. 1 illustrates an exemplary overview apparatus for making adetermination about the eye of a subject in ambient lighting conditions.As shown in FIG. 1, one embodiment of the apparatus 100 comprises animage capture mechanism 102. In one aspect, the image capture mechanism102 can be camera. The image capture mechanism 102 can take still and/orvideo images. Generally, the image capture mechanism 102 will be adigital camera, but can be an analog device equipped with or incommunication with an appropriate analog/digital converter. The imagecapture mechanism 102 may also be a webcam, scanner, recorder, or anyother device capable of capturing a still image or a video.

In one aspect, the image capture mechanism 102 is in directcommunication with a computing device 110 through, for example, anetwork (wired (including fiber optic), wireless or a combination ofwired and wireless) or a direct-connect cable (e.g., using a universalserial bus (USB) connection, IEEE 1394 “Firewire” connections, and thelike). In other aspects, the image capture mechanism 102 can be locatedremotely from the computing device 110, but capable of capturing animage and storing it on a memory device such that the image can bedownloaded or transferred to the computing device 110 using, forexample, a portable memory device and the like. In one aspect, thecomputing device 110 and the image capture mechanism 102 can comprise orbe a part of a device such as a smart phone, table, laptop computer orany other mobile computing device.

In a basic configuration, the computing device 110 can be comprised of aprocessor 104 and a memory 108. The processor 104 can executecomputer-readable instructions that are stored in the memory 108.Moreover, images captured by the image capture device 102, whether stillimages or video, can be stored in the memory 108 and processed by theprocessor 104 using computer-readable instructions stored in the memory108.

The processor 104 is in communication with the image capture device 102and the memory 108. The processor 104 can execute computer-readableinstructions stored on the memory 108 to capture, using the imagecapture device 102, an image of an eye 106 of a subject. No lightsource, other than ambient lighting, is required to capture the image.The image is captured using only ambient lighting conditions and doesnot require an additional light source to be directed into the eye 106.While capturing the image of the eye 106, non-relevant reflections fromthe eye 106 of the subject are managed.

The processor 104 can further execute computer-readable instructionsstored on the memory 108 to detect, from the image of the eye 106 of thesubject, ambient light reflected out of the eye 106 of the subject fromthe retina of the eye 106 of the subject and to make a determinationabout the eye 106 of the subject based upon the detected reflectedambient light. Generally, the processor 104 of the apparatus 100executing computer-readable instructions stored in the memory 108 thatcause the processor 104 to make a determination about the eye 106 of thesubject based at least in part on an aspect of the reflected ambientlight. Such aspects can include, for example, an overall brightness orintensity of the reflected ambient light as determined in a plurality ofpixels of the image acquired by the image capture device 102. Theaspects can also include one or more colors of the reflected ambientlight also as determined from the plurality of pixels of the imageacquired by the image capture device 102. For example, the processor 104executing computer-readable instructions stored in the memory 108 cancause the processor 104 to make a determination about the eye 106 basedat least in part on the overall brightness or intensity of the red,green and blue pixels that comprise the reflected ambient light asdetermined from the image acquired by the image capture device. Overallbrightness can be determined, as a non-limiting example, using methodsand software developed by Allan Hanbury (see, for example, “A 3D-PolarCoordinate Colour Representation Well Adapted to Image Analysis,”Hanbury, Allan; Vienna University of Technology, Vienna, Austria, 2003),which is fully incorporated herein by reference and made a part hereof.The processor 104 also uses the relative intensity of red, green or bluefound in the plurality of pixels of the image acquired by the imagecapture device 102 to make the determination about the eye 106. Forexample, using at least in part on an aspect of the reflected ambientlight as determined from an image of the eye 106 as captured by theimage capture device 102, the processor 104 executing computer-readableinstructions stored in the memory 108 can make determinations about theeye 106 comprising a refractive error for the eye 106 of the subject. Inother words, using at least in part an overall brightness or intensityof the reflected ambient light as determined in a plurality of thepixels of the image acquired by the image capture device 102 and therelative intensity of one or more colors of the reflected ambient lightalso as determined from the plurality of pixels of the image acquired bythe image capture device 102, the processor 104 executingcomputer-readable instructions stored in the memory 108 can makedeterminations about the eye 106 including a refractive error for theeye 106 of the subject.

As shown in FIG. 2A, the image capture device 102 of the apparatus 100captures an image (FIG. 2B) 208 of the eye 106. The processor 104 of theapparatus 100 can execute computer-readable instructions stored in thememory 108 that cause the processor 104 to detect, from the image 208 ofthe eye, ambient light 202 reflected 204 out of an eye 106 of thesubject from the retina 206 of the eye 106 of the subject and determinethe overall intensity of the plurality of pixels (example pixels areshown in FIG. 2B as white “x” in the pupil 210 of the image 208 of theeye) within the pupil 210 or a portion of the pupil 210; determine anintensity of a first color from a the plurality of pixels located withinthe pupil 210 or at least a portion of a pupil 210 of the eye of thesubject captured in the image 208; determine an intensity of a secondcolor from the plurality of pixels located within the pupil 201 or atleast a portion of the pupil 210 of the eye of the subject captured inthe image 208; and calculate refractive error or glasses prescriptionbased on regression analysis. The regression analysis includes at leastone of the following elements (1) the overall intensity or brightness ofthe pixels within pupil 210 or a portion of the pupil 210; and (2) therelative intensity of a first color from a first one or more pixelslocated within at least a portion of a pupil 210 of the eye of thesubject captured in image 208 as compared to a second color from asecond one or more pixels located within the at least a portion of thepupil 210 of the eye of the subject captured in image 208. Optionally,the regression analysis can also include (3) the color of the iris ofthe subject captures in image 208; and (4) the overall intensity of theambient lighting at the time the image is captured with the imagecapturing device 100. For example, when the intensity of the first coloris brighter relative to the intensity of the second color and theoverall intensity is relatively brighter, the determination about theeye of the subject based upon the reflected ambient light can comprise apositive value or hyperopia. Alternatively, when the intensity of thefirst color is dimmer relative to the intensity of the second color andthe overall intensity is relatively dimmer, the determination about theeye of the subject based upon the reflected ambient light can comprise anegative value or myopia.

For example, the first color can comprise any one or any combination ofred, green, and blue and the second color can comprise any one orcombination of red, green, and blue that is not used as the first color.

By performing the steps described above, the processor 104 of theapparatus 100 can execute computer-readable instructions stored in thememory 108 that cause the processor 104 to make an autorefraction or aphotorefraction measurement. For example, as shown in FIG. 2C, theapparatus 100 can capture, using the image capture device 102, an image208 of the eye 106 of the subject using only ambient lighting 202conditions through a spectacle lens or a contact lens (both shown as 212in FIG. 2C) while the subject is wearing the spectacle lens or thecontact lens 212 over the eye 106. The image capturing device 102 of theapparatus 100 then captures a second image using only ambient lighting202 conditions while the subject is not wearing the spectacle lens orthe contact lens 212 over the eye (see, for example, FIG. 2A) and theprocessor 104 executes computer-readable instructions stored in thememory 108 that cause the processor 104 to compare the first image tothe second image and the determination about the eye of the subjectbased upon the reflected 204 ambient light is based on the comparisonand comprises an estimated prescription for the spectacle lens or thecontact lens 212.

Referring now to FIG. 2D, in yet another aspect, the processor 104 canexecute computer-readable instructions stored in the memory 108 thatcause the processor 104 to make a first determination about the eye 106of the subject based upon the reflected ambient light from a firstplurality of pixels 220 located within the at least a portion of thepupil 210 of the eye 106 of the subject captured in the image 208; makea second determination from a second plurality of pixels 222 locatedwithin the at least a portion of the pupil 210 of the eye 106 of thesubject captured in the image 208, wherein the second plurality ofpixels 222 are a subset of the first plurality of pixels 210; make athird determination from a third plurality of pixels 224 located withinthe at least a portion of the pupil 210 of the eye 106 of the subjectcaptured in the image 208, wherein the third plurality of pixels 224 area subset of the first plurality of pixels 210 and are separate from thesecond plurality of pixels 222; and compare the first determination, thesecond determination and the third determination to make thedetermination about the eye 106 of the subject based upon the reflectedambient light. For example, comparing the first determination, thesecond determination and the third determination to make thedetermination about the eye 106 of the subject based upon the reflectedambient light can comprise one or more of determining a standarddeviation of the first determination to the second determination, astandard deviation of the first determination to the seconddetermination, or a standard deviation of the second determination tothe third determination, wherein the determined standard deviationindicates the determination about the eye 106 of the subject based uponthe reflected ambient light. The determination made about the eye 106 ofthe subject based upon the reflected ambient light can be the presenceor absence of astigmatism. The amount of astigmatism, once detected, canbe determined by comparing the overall intensity and the relativeintensity of the first color or the relative intensity of the secondcolor of various regions of the pupil. For example, measuring one ormore of hyperopia or myopia at the various regions of the pupil usingthe apparatus 100, as described herein, can be used to determine theamount of astigmatism present in the eye 106.

Consider the following example, again referring to FIG. 2D. If adetermination of the eyes using the methods and apparatus describedherein on the central region of the pupil (entire white dashed circle)220 for someone with myopia (Ex: −2.00) and no astigmatism, a value of−2.00 would also be obtained in the sub-regions at 90 degrees (solidsquare) 222 and 0 degrees (dashed square) 224. If someone hasastigmatism, a refractive error of −2.00 may be obtained if the wholepupil central region of the pupil (entire white dashed circle) 210 isanalyzed using the methods and apparatus described herein, but if thesub-region at 90 degrees (solid square) 222 is analyzed and determinedto have a refractive error of −1.00 and the sub-region at 0 degrees(dashed square) 224 is analyzed and determined to have a refractiveerror of −3.00, the standard deviation would be higher in the case ofastigmatism where the sub-regions 222, 224 would be −1.00 and −3.00,respectively. Thus, a prescription for corrective lenses also needs tobe −1.00 and −3.00 in those two sub-regions 222, 224, rather than anoverall −2.00 for the central pupil region 220. These numbers are alsojust examples. They could be positive, negative, or both (one of each).Also, many sub-regions can be evaluated to make a determination aboutthe eye. In this example the two sub-regions are at 90 degrees and 0degrees, but they could be at any location throughout the pupil 210.

As described herein, the apparatus 100 or the image capture device 102can manage non-relevant reflections from a cornea and a lens of the eye106 of the subject while capturing the image 208. Such non-relevantreflections can affect the determination about the eye of the subjectbased upon the reflected ambient light. Managing the non-relevantreflections can include, for example and as shown in FIG. 2E, the use ofa polarizing filter 214, wherein non-relevant reflections 216 from theeye 106 are managed while capturing the image 208 by placing thepolarizing filter 214 over a lens of the image capture device 102 orbetween the image capture device 102 and the eye 106 of the subject whencapturing the image 208.

In yet another aspect, as shown in FIG. 2F, the apparatus 100 canfurther comprise a surface 218, wherein non-relevant reflections 216from the eye 106 are managed while capturing the image 208 comprise thesurface 218 absorbing light or preventing the non-relevant reflections216 from the eye 106 while capturing the image 208. For example, whenacquiring the image 208 the apparatus 100 including the image capturedevice 102 can be placed close to the eye 106 such that non-relevantreflections 216 are minimized and those that do occur are absorbed orprevented by the surface 218. For example, the apparatus 100 includingthe image capture device 102 can be placed from approximately 4 to 10 cmaway from the eye 106 while capturing the image 208, or the apparatus100 including the image capture device 102 can be placed fromapproximately 8 to 9 cm away from the eye 106 while capturing the image208. The surface 218 can comprise, for example, a surface having a blackmatte finish to facilitate the absorption of ambient light and preventof non-relevant reflections. The surface 218 can comprise a portion ofthe image capture device 102 or the apparatus 100, including a case thatmay house at least a portion of the image capture device 102 or theapparatus 100. For example, the image capture device 102 may comprise atleast a portion of a smart phone or other mobile computing device havinga camera and the surface 218 can be at least a portion of a case thathouses the smart phone or other mobile computing device having a camera.

This disclosure contemplates apparatus that can be used makedeterminations about the eye 106 in eyes that have smaller than averagepupil diameters such as, for example, approximately 2 mm or less. Thisis currently a challenge for many photorefractors that require assessingthe slope of the reflected light over a wide pupil diameter, making itis less useful in more brightly lit rooms or in older patients who havesmaller pupils. Further, embodiments of the apparatus described hereincan monitor the reflected light in just the center region of the pupilin this measurement allowing accurate measurement of the smaller pupil.

Further, embodiments of the apparatus described herein can monitor thereflected light in a natural pupil or an artificial pupil. Anartificial, or second pupil can be optically created for an eye bycombining lenses and apertures, without placing anything inside the eye.Vision scientists regularly create what is called a Maxwellian Viewduring experiments where they want to give all subjects the same pupilsize by creating an artificial pupil. An artificial pupil could beoptically created or physically created by placing an aperture in frontof the eye.

Alternatively or optionally, the apparatus 100 as described herein canbe used to make a determination of the subject's left eye or right eye.Similarly, it can be used to make a determination of the subject's lefteye and right eye.

Though not shown in FIG. 1, the apparatus 100 can optionally include alight meter or any other mechanism for measure ambient lighting levels.The light meter can detect an intensity for the ambient light conditionsand provide an indication if the ambient light conditions are too lowfor the apparatus 100 to capture an image of the eye of the subjectbased upon the reflected ambient light. In another aspect, the lightmeter can measure ambient lighting conditions and such measurement canbe used to adjust the image or the calculation of refractive error usingregression analysis accordingly.

When the logical operations described herein are implemented insoftware, the process may execute on any type of computing architectureor platform. Such a computing device 300 as shown in FIG. 3 can be thesame as computing device 110, described above, or used alternatively forcomputing device 110. For example, referring to FIG. 3, an examplecomputing device 300 upon which embodiments of the invention may beimplemented is illustrated. The computing device 300 can optionally be amobile computing device such as a laptop computer, a tablet computer, amobile phone and the like. The computing device 300 may include a bus orother communication mechanism for communicating information amongvarious components of the computing device 300. In its most basicconfiguration, computing device 300 typically includes at least oneprocessing unit 306 and system memory 304. Depending on the exactconfiguration and type of computing device, system memory 304 may bevolatile (such as random access memory (RAM)), non-volatile (such asread-only memory (ROM), flash memory, etc.), or some combination of thetwo. This most basic configuration is illustrated in FIG. 3 by dashedline 302. The processing unit 306 may be a standard programmableprocessor that performs arithmetic and logic operations necessary foroperation of the computing device 300.

Computing device 300 may have additional features/functionality. Forexample, computing device 300 may include additional storage such asremovable storage 308 and non-removable storage 310 including, but notlimited to, magnetic or optical disks or tapes. Computing device 300 mayalso contain network connection(s) 316 that allow the device tocommunicate with other devices. Computing device 300 may also have inputdevice(s) 314 such as a keyboard, mouse, touch screen, etc. Outputdevice(s) 312 such as a display, speakers, printer, etc. may also beincluded. The additional devices may be connected to the bus in order tofacilitate communication of data among the components of the computingdevice 300. All these devices are well known in the art and need not bediscussed at length here.

The processing unit 306 may be configured to execute program codeencoded in tangible, computer-readable media. Computer-readable mediarefers to any media that is capable of providing data that causes thecomputing device 300 (i.e., a machine) to operate in a particularfashion. Various computer-readable media may be utilized to provideinstructions to the processing unit 306 for execution. Common forms ofcomputer-readable media include, for example, magnetic media, opticalmedia, physical media, memory chips or cartridges, or any othernon-transitory medium from which a computer can read. Examplecomputer-readable media may include, but is not limited to, volatilemedia, non-volatile media and transmission media. Volatile andnon-volatile media may be implemented in any method or technology forstorage of information such as computer readable instructions, datastructures, program modules or other data and common forms are discussedin detail below. Transmission media may include coaxial cables, copperwires and/or fiber optic cables, as well as acoustic or light waves,such as those generated during radio-wave and infra-red datacommunication. Example tangible, computer-readable recording mediainclude, but are not limited to, an integrated circuit (e.g.,field-programmable gate array or application-specific IC), a hard disk,an optical disk, a magneto-optical disk, a floppy disk, a magnetic tape,a holographic storage medium, a solid-state device, RAM, ROM,electrically erasable program read-only memory (EEPROM), flash memory orother memory technology, CD-ROM, digital versatile disks (DVD) or otheroptical storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices.

In an example implementation, the processing unit 306 may executeprogram code stored in the system memory 304. For example, the bus maycarry data to the system memory 304, from which the processing unit 306receives and executes instructions. The data received by the systemmemory 304 may optionally be stored on the removable storage 308 or thenon-removable storage 310 before or after execution by the processingunit 306.

Computing device 300 typically includes a variety of computer-readablemedia. Computer-readable media can be any available media that can beaccessed by device 300 and includes both volatile and non-volatilemedia, removable and non-removable media. Computer storage media includevolatile and non-volatile, and removable and non-removable mediaimplemented in any method or technology for storage of information suchas computer readable instructions, data structures, program modules orother data. System memory 304, removable storage 308, and non-removablestorage 310 are all examples of computer storage media. Computer storagemedia include, but are not limited to, RAM, ROM, electrically erasableprogram read-only memory (EEPROM), flash memory or other memorytechnology, CD-ROM, digital versatile disks (DVD) or other opticalstorage, magnetic cassettes, magnetic tape, magnetic disk storage orother magnetic storage devices, or any other medium which can be used tostore the desired information and which can be accessed by computingdevice 300. Any such computer storage media may be part of computingdevice 300.

It should be understood that the various techniques described herein maybe implemented in connection with hardware or software or, whereappropriate, with a combination thereof. Thus, the methods andapparatuses of the presently disclosed subject matter, or certainaspects or portions thereof, may take the form of program code (i.e.,instructions) embodied in tangible media, such as floppy diskettes,CD-ROMs, hard drives, or any other machine-readable storage mediumwherein, when the program code is loaded into and executed by a machine,such as a computing device, the machine becomes an apparatus forpracticing the presently disclosed subject matter. In the case ofprogram code execution on programmable computers, the computing devicegenerally includes a processor, a storage medium readable by theprocessor (including volatile and non-volatile memory and/or storageelements), at least one input device, and at least one output device.One or more programs may implement or utilize the processes described inconnection with the presently disclosed subject matter, e.g., throughthe use of an application programming interface (API), reusablecontrols, or the like. Such programs may be implemented in a high levelprocedural or object-oriented programming language to communicate with acomputer system. However, the program(s) can be implemented in assemblyor machine language, if desired. In any case, the language may be acompiled or interpreted language and it may be combined with hardwareimplementations.

The techniques for making a determination about an eye in ambientlighting conditions described herein can optionally be implemented witha mobile computing device, such as a laptop computer, tablet computer ormobile phone. Accordingly, the mobile computing device is extremelysmall compared to conventional devices and is very portable, whichallows the mobile computing device to be used wherever needed. Manyconventional devices have a chin rest that requires the subjects to onlylook straight ahead during this testing. Unlike conventional devices,the mobile computing device can be placed in any position relative tothe subject's head where the eyes can still be viewed and measurementscan be made.

It should be appreciated that the logical operations described hereinwith respect to the various figures may be implemented (1) as a sequenceof computer implemented acts or program modules (i.e., software) runningon a computing device, (2) as interconnected machine logic circuits orcircuit modules (i.e., hardware) within the computing device and/or (3)a combination of software and hardware of the computing device. Thus,the logical operations discussed herein are not limited to any specificcombination of hardware and software. The implementation is a matter ofchoice dependent on the performance and other requirements of thecomputing device. Accordingly, the logical operations described hereinare referred to variously as operations, structural devices, acts, ormodules. These operations, structural devices, acts and modules may beimplemented in software, in firmware, in special purpose digital logic,and any combination thereof. It should also be appreciated that more orfewer operations may be performed than shown in the figures anddescribed herein. These operations may also be performed in a differentorder than those described herein.

FIG. 4 illustrates an example method for making a determination about aneye of a subject based upon ambient light reflected out of the eye. Themethod comprises step 402, detecting, using a computing device, ambientlight reflected out of an eye of a subject from a retina of the eye ofthe subject; and step 404, making a determination about the eye of thesubject based upon the reflected ambient light.

Making the determination about the eye of the subject based upon thereflected ambient light comprises making a determination based at leastin part on an aspect of the reflected ambient light. The aspects caninclude making a determination based at least in part on an overallbrightness (luminescence) of an image of the eye and the intensity ofone or more colors of the reflected ambient light. Consider onenon-limiting example where the determination about the eye of thesubject comprises refractive error and the refractive error isdetermined by a formula developed through regression analysis. Theexample formula considers overall brightness (“LuminancePupil”) of thepupil from the image capture using only ambient light and the intensityof blue from one or more pixels from the pupil in the image(“BluePixel”), the intensity of red in one or more pixels from the pupilin the image (“RedPixel”), and the intensity of green in one or morepixels from the pupil in the image (“GreenPixel”) while controlling forambient light levels (“LuminanceAmbient”). The example formulacomprises: RefractiveError=−36.47+(−638.37*RedPixel)+(−1807.2*GreenPixel)+(−333.64*BluePixel)+(2156.5*LuminancePupil)+(183.0*LuminanceAmbient)+(890.2*GreenPixel*LuminanceAmbient)+(−4895.0*RedPixel*RedPixel)+(−8457.1*GreenPixel*GreenPixel)+(−1711.4*BluePixel*BluePixel)+(1592.8*LuminancePupil*LuminancePupil)+(−178.7*LuminanceAmbient*LuminanceAmbient),and has an R² of approximately 0.78 for fitting the measurement to theintended refractive error of the eye. It is to be appreciated that thisis only one example of a formula for making a determination about theeye and other formulas are contemplated within the scope of thisdisclosure.

Referring back to the method described in FIG. 4, detecting ambientlight reflected out of an eye of a subject from a retina of the eye ofthe subject can further comprise capturing, using an image capturedevice, an image of the eye of a subject, wherein the image is capturedusing only ambient lighting conditions and wherein non-relevantreflections from the eye of the subject are managed while capturing theimage; determining, using the computing device, an overall intensity oflight from a plurality of pixels located within at least a portion of apupil captured in the image; determining, using the computing device, afirst intensity of a first color from the plurality of pixels locatedwithin at least a portion of a pupil of the eye of the subject capturedin the image; determining, using the computing device, a secondintensity of a second color from the plurality of pixels located withinthe at least a portion of the pupil of the eye of the subject capturedin the image; and comparing, by the computing device, a relativeintensity of the first color and a relative intensity of the secondcolor, wherein the comparison and the overall intensity are used to makethe determination about the eye of the subject based upon the reflectedambient light. For example, when the intensity of the first color isbrighter relative to the intensity of the second color and an overallintensity is relatively brighter, the determination about the eye of thesubject based upon the reflected ambient light comprises a positivevalue or hyperopia. Conversely, when the intensity of the first color isdimmer relative to the intensity of the second color and an overallpixel intensity is relatively dimmer, the determination about the eye ofthe subject based upon the reflected ambient light comprises a negativevalue or myopia. The first color can comprise any one or any combinationof red green and blue and the second color can comprise any one or anycombination of red, green and blue.

In the method of FIG. 4, the determination about the eye of the subjectbased upon the reflected ambient light can alternatively or optionallycomprise an autorefraction or a photorefraction measurement. Capturing,using the image capture device, an image of the eye of the subject cancomprise capturing a first image using only ambient lighting conditionswith the image capture device through a spectacle lens or a contact lenswhile the subject is wearing the spectacle lens or the contact lens overthe eye and capturing a second image using only ambient lightingconditions with the image capture device while the subject is notwearing the spectacle lens or the contact lens over the eye and theaspects of the reflected ambient light in the first image can becompared to the aspects of the reflected ambient light in the secondimage and the determination about the eye of the subject based upon thereflected ambient light is based on the comparison and comprises anestimated prescription for the spectacle lens or the contact lens.

The method shown in FIG. 4 can further comprise making a firstdetermination about the eye of the subject based upon the reflectedambient light from a first plurality of pixels located within theportion of the pupil of the eye of the subject captured in the image;making a second determination from a second plurality of pixels locatedwithin the portion of the pupil of the eye of the subject captured inthe image, wherein the second plurality of pixels are a subset of thefirst plurality of pixels; making a third determination from a thirdplurality of pixels located within the portion of the pupil of the eyeof the subject captured in the image, wherein the third plurality ofpixels are a subset of the first plurality of pixels and are separatefrom the second plurality of pixels; and comparing the firstdetermination, the second determination and the third determination tomake the determination about the eye of the subject based upon thereflected ambient light. Comparing the first determination, the seconddetermination and the third determination to make the determinationabout the eye of the subject based upon the reflected ambient light cancomprise one or more of determining a standard deviation of the firstdetermination to the second determination, a standard deviation of thefirst determination to the second determination, or a standard deviationof the second determination to the third determination, wherein thedetermined standard deviation indicates the determination about the eyeof the subject based upon the reflected ambient light. For example, thedetermination about the eye of the subject based upon the reflectedambient light can be the presence or the absence of astigmatism. Whenthe presence of astigmatism is detected, an amount of astigmatism can bedetermined by comparing the overall intensity and the relative intensityof the first color or the relative intensity of the second color ofvarious regions of the pupil. Such measurements of various regions ofthe pupil can comprise measuring one or more of hyperopia or myopia atthe various regions of the pupil.

As noted above, the method of FIG. 4 can include managing non-relevantreflections from the eye while capturing the image, which can comprisemanaging reflections from a cornea or a lens of the eye of the subjectwhile capturing the image. For example, a polarizing filter can beplaced over a lens of the image capture device or between the imagecapture device and the eye of the subject. Managing non-relevantreflections from the eye while capturing the image can also compriseblocking light that would lead to reflections from a corneal surface ofthe eye or a lens of the eye. For example, a surface can be providedthat absorbs light or prevents the non-relevant reflections from the eyewhile capturing the image. In one aspect, the surface can have a blackmatte finish. In various aspects the surface can comprise a portion ofthe image capture device or at least a portion of a case that houses theimage capture device.

FIG. 5 illustrates an alternate example method for making adetermination about an eye of a subject based upon ambient lightreflected out of the eye. The method comprises step 502, capturing,using an image capture device, an image of an eye of a subject, whereinsaid image is captured using only ambient lighting conditions andwherein non-relevant reflections from a cornea and a lens of the eye ofthe subject are managed while capturing the image. At step 504, anaverage red intensity can be determined from a plurality of pixelslocated within at least a portion of a pupil captured in the image. Atstep 506, an average blue intensity is determined from the plurality ofpixels located within the at least a portion of a pupil captured in theimage. At step 508, an overall intensity is determined of the pluralitypixels located within the at least a portion of a pupil captured in theimage; and, at step 510, compare the average red intensity and theaverage blue intensity, wherein the comparison and the determinedoverall intensity are used to determine an optical quality of the eye.

In the method of FIG. 5, the determination about the eye of the subjectbased upon the reflected ambient light can alternatively or optionallycomprise an autorefraction or a photorefraction measurement. Capturing,using the image capture device, an image of the eye of the subject cancomprise capturing a first image using only ambient lighting conditionswith the image capture device through a spectacle lens or a contact lenswhile the subject is wearing the spectacle lens or the contact lens overthe eye and capturing a second image using only ambient lightingconditions with the image capture device while the subject is notwearing the spectacle lens or the contact lens over the eye and theaspects of the reflected ambient light in the first image can becompared to the aspects of the reflected ambient light in the secondimage and the determination about the eye of the subject based upon thereflected ambient is based on the comparison and comprises an estimatedprescription for the spectacle lens or the contact lens.

The method shown in FIG. 5 can further comprise determining a presenceor an absence of astigmatism. If the presence of astigmatism isindicated, an amount of astigmatism can be determined by comparingoptical quality measurements of various regions of the pupil. Suchoptical quality measurements of various regions of the pupil cancomprise measuring one or more of hyperopia or myopia at the variousregions of the pupil.

As noted above, the method of FIG. 5 can include managing non-relevantreflections from the eye while capturing the image, which can comprisemanaging reflections from a cornea or a lens of the eye of the subjectwhile capturing the image. For example, a polarizing filter can beplaced over a lens of the image capture device or between the imagecapture device and the eye of the subject. Managing non-relevantreflections from the eye while capturing the image can also compriseblocking light that would lead to reflections from a corneal surface ofthe eye or a lens of the eye. For example, a surface can be providedthat absorbs light or prevents the non-relevant reflections from the eyewhile capturing the image. In one aspect, the surface can have a blackmatte finish. In various aspects the surface can comprise a portion ofthe image capture device or at least a portion of a case that houses theimage capture device.

As used herein, at least one of the subject's eyes can be the subject'sleft eye or right eye. Alternatively, at least one of the subject's eyescan be the subject's left eye and right eye. This disclosurecontemplates that the optical qualities based on the subject's left eyeand right eye can be the same or different.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

What is claimed:
 1. A method comprising: capturing, using an imagecapture device, an image of an eye of a subject, wherein said image iscaptured using only ambient lighting conditions and wherein non-relevantreflections from a cornea and a lens of the eye of the subject aremanaged while capturing the image; determining, using a computingdevice, an overall intensity of light from a plurality of pixels locatedwithin at least a portion of a pupil captured in the image, wherein theplurality of pixels comprise red, green, and blue pixels; determining,using the computing device, an average red intensity from the pluralityof pixels located within the at least a portion of the pupil captured inthe image; determining, using the computing device, an average blueintensity from the plurality of pixels located within the at least aportion of a pupil captured in the image; and determining, by thecomputing device, using the average red intensity, the average blueintensity and the determined overall intensity an optical quality of theeye.
 2. The method of claim 1, wherein the determined optical quality ofthe eye comprises an autorefraction or photorefraction measurement. 3.The method of claim 1, wherein capturing, using the image capturedevice, an image of the eye of the subject comprises capturing a firstimage using only ambient lighting conditions with the image capturedevice through a spectacle lens or a contact lens while the subject iswearing the spectacle lens or the contact lens over the eye andcapturing a second image using only ambient lighting conditions with theimage capture device while the subject is not wearing the spectacle lensor the contact lens over the eye and the first image is compared to thesecond image and the determined optical quality of the eye is based onthe comparison and comprises an estimated prescription for the spectaclelens or the contact lens.
 4. The method of claim 1, wherein the averagered intensity is brighter relative to the average blue intensity and theoverall intensity is relatively brighter, and the determined opticalquality of the eye is a positive value or hyperopia.
 5. The method ofclaim 1, wherein the average red intensity is dimmer relative to theaverage blue intensity and the overall intensity is relatively dimmer,and the determined optical quality of the eye is a negative value ormyopia.
 6. The method of claim 1, wherein the method further comprises:making a first determined optical quality about the eye of the subjectbased upon the reflected ambient light from a first plurality of pixelslocated within the at least a portion of the pupil of the eye of thesubject captured in the image; making a second determined opticalquality about the eye from a second plurality of pixels located withinthe at least a portion of the pupil of the eye of the subject capturedin the image, wherein the second plurality of pixels are a subset of thefirst plurality of pixels; making a third determined optical qualityabout the eye from a third plurality of pixels located within the atleast a portion of the pupil of the eye of the subject captured in theimage, wherein the third plurality of pixels are a subset of the firstplurality of pixels and are separate from the second plurality ofpixels; and comparing the first determined optical quality, the seconddetermined optical quality and the third determined optical quality tomake the determined optical quality about the eye of the subject basedupon the reflected ambient light.
 7. The method of claim 6, whereincomparing the determined optical quality, the second determined opticalquality and the third determined optical quality to make thedetermination about the eye of the subject based upon the reflectedambient light comprises one or more of determining a standard deviationof the first determination to the second determination, a standarddeviation of the first determination to the second determined opticalquality, or a standard deviation of the second determined opticalquality to the third determined optical quality, wherein the determinedstandard deviation indicates the determined optical quality about theeye of the subject based upon the reflected ambient light.
 8. The methodof claim 6, wherein the determined optical quality of the eye is apresence or an absence of astigmatism.
 9. The method of claim 8, whereinthe presence of astigmatism is detected and an amount of astigmatism isdetermined by comparing the overall intensity and the average redintensity or the average blue intensity of various regions of the pupil.10. The method of claim 9, wherein the amount of astigmatism isdetermined by measuring one or more of hyperopia or myopia at thevarious regions of the pupil.
 11. The method of claim 1, whereinmanaging non-relevant reflections from the cornea and the lens of theeye of the subject while capturing the image comprises placing apolarizing filter over a lens of the image capture device or between theimage capture device and the eye of the subject.
 12. The method of claim1, wherein managing non-relevant reflections from the cornea and thelens of the eye of the subject while capturing the image comprisesblocking light that would lead to reflections from a corneal surface orthe lens of the eye.
 13. The method of claim 12, wherein the imagecapture device further comprises a surface having a black matte finishand wherein blocking light that would lead to reflections from a cornealsurface or the lens of the eye comprises the surface absorbing light orpreventing reflections from the corneal surface or the lens of the eyecaused by the ambient lighting conditions.
 14. The method of claim 13,wherein the surface comprises at least a portion of a case that housesthe image capture device.
 15. The method of claim 1, wherein the imagecapture device comprises a smart phone or other mobile computing devicehaving a camera.
 16. The method of claim 1, wherein the image capturedevice captures a still image or a video of the eye of the subject. 17.The method of claim 1, wherein the subject's pupil has a diameter ofapproximately 2 mm or less.
 18. The method of claim 1, wherein thesubject's pupil is a natural pupil.
 19. The method of claim 1, whereinthe subject's pupil is an artificial pupil.
 20. The method of claim 1,wherein the eye of the subject is the subject's left eye or right eye.21. The method of claim 1, wherein the eye of the subject is thesubject's left eye and right eye.
 22. The method of claim 1, furthercomprising detecting an intensity for the ambient light conditions andproviding an indication if the ambient light conditions are too low forthe image capture device to capture the image of the eye of the subject.